The Southwest Oncology Group is a major extramural cooperative therapeutic research organization supported by the National Cancer Institute. The Group has been chaired by Dr. Barth Hoogstraten for the past eight years, with Headquarters at the University of Kansas. In February 1981, Dr. Hoogstraten resigned and in March 1981 Dr. Charles A. Coltman, Jr. was elected Chairman of the Group. This change in leadership has resulted in the need to move the Headquarters office from Kansas City to San Antonio. This grant reapplication has been necessitated by this change. The Group Operations Office will be housed at the Cancer Therapy and Research Center in San Antonio, on the campus of the South Texas Medical Center, one block from the University of Texas Health Science Center at San Antonio. The aim is to develop the Southwest Oncology Group into a model of cooperative therapeutic research for the future. There will be some reorganization of the Operations Office as well as the administrative structure of the Group to accomplish this aim.